Nuclear Data Sheets for A = 122

Nuclear Data Sheets for A = 84

Nuclear Data Sheets for A = 82☆

The Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei, GRIFFIN, is a new experimental facility for radioactive decay studies at the TRIUMF-ISAC laboratory. The performance of the 16 high-purity germanium (HPGe) clover detectors that will make up the GRIFFIN spectrometer is reported. The energy resolution, efficiency, timing resolution, crosstalk and preamplifier properties of each crystal were measured using a combination of analog and digital data acquisition techniques. The absolute efficiency and add-back factors are determined for the energy range of 80–3450 keV. The detectors show excellent performance with an average over all 64 crystals of a FWHM energy resolution of 1.89(6) keV and relative efficiency with respect to a 3 in . × 3 in . NaI detector of 41(1)% at 1.3 MeV.

Characteristics of GRIFFIN high-purity germanium clover detectors

Gamma ray spectra of two (p,γ) resonances have been utilised for the characterisation of the Clover detector at energies beyond 5 MeV. Apart from the efficiency and the resolution of the detector, the shapes of the full energy peaks as well as the nature of the escape peaks which are also very crucial at higher energies have been analysed with special attention. Proper gain matching in software have checked deterioration in the energy resolution and distortion in the peak shape due to addback. The addback factors show sharp increasing trend even at energies around 11 MeV.

Characterisation of a Compton suppressed Clover detector for high energy gamma rays (⩽11MeV)

The Clover detectors in their addback mode are excellent tools for detecting high-energy gamma rays (⩾2 MeV ) . The characteristics of these detectors, at energies above 2 MeV , are usually determined from simulation data or from extrapolation of the empirical data. This is the first time that the characteristics of a Compton suppressed Clover germanium detector have been studied up to 5 MeV using a radioactive 66 Ga (T 1/2 =9.41 h ) source.

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Characteristics of a Compton suppressed Clover detector up to 5 MeV

Lifetimes of eight high spin states were measured in the yrast band of even-even nucleus ${}^{80}\mathrm{Kr}$ by Doppler shift attenuation method. High spin states were populated by the heavy ion fusion evaporation reaction ${}^{65}\mathrm{Cu}{(}^{19}\mathrm{F}{,2p2n)}^{80}\mathrm{Kr}.$ The transition quadrupole moments, extracted from the lifetimes of the states, show a decreasing tendency after the band crossing indicating a change in shape of ${}^{80}\mathrm{Kr}$ at high spin. The total Routhian surface calculations, using Woods-Saxon mean field potential and BCS pairing with Strutinsky shell correction procedure, predict a change from a near oblate to near prolate shape with small deformation along the yrast band at high spin in ${}^{80}\mathrm{Kr}.$ The present experimental ${Q}_{t}$ values and the second alignment in the yrast band of ${}^{80}\mathrm{Kr}$ support the predicted change in shape.

Shape of 80 Kr at high spin

The high spin levels of $^{84}\mathrm{Y}$ have been established up to 12 MeV excitation energy and probable spin of ${25}^{+}$ through the reaction $^{59}\mathrm{Co}$${(}^{28}$Si,2pn${)}^{84}$Y using in-beam \ensuremath{\gamma}-ray spectroscopic techniques The \ensuremath{\gamma} transitions in $^{84}\mathrm{Y}$ have been identified through the particle-gamma coincidences The level scheme was constructed through the \ensuremath{\gamma}-\ensuremath{\gamma} coincidences, angular distribution, and directional correlation orientation ratios The positive parity yrast band built on the (\ensuremath{\pi}${\mathit{g}}_{9/2}$\ensuremath{\bigotimes}\ensuremath{\nu}${\mathit{g}}_{9/2}$) configuration shows a large signature splitting and a signature inversion at I\ensuremath{\sim}11\ensuremath{\Elzxh} The measured B(E2; I\ensuremath{\rightarrow}I-2) values give a deformation ${\mathrm{\ensuremath{\beta}}}_{2}$\ensuremath{\sim}017 The negative parity band shows a signature inversion at I\ensuremath{\sim}11\ensuremath{\Elzxh} and B(M1; I\ensuremath{\rightarrow}I-1) enhancement for Ig11\ensuremath{\Elzxh} The projected Hartree-Fock and the cranked shell model calculations provide an understanding for the observed properties of the energy levels in $^{84}\mathrm{Y}$

High spin structure of 84Y.

The high spin states of {sup 82}Zr have been studied through the {sup 58}Ni({sup 27}Al, p2n){sup 82}Zr reaction using a 92 MeV {sup 27}Al beam up to an excitation energy {approximately}5.2 MeV and a spin of 12{h_bar}. The electromagnetic transition probabilities were obtained from the lifetimes of nuclear states measured with recoil distance and line shape analysis methods. The measured lifetimes indicate a reduction in Q{sub t} values in going from 2{sup +} to 4{sup +} state. {copyright} {ital 1997} {ital The American Physical Society}

S. D. Paul

Papers

Characteristics of a Compton suppressed Clover detector up to 5 MeV

Shape of 80 Kr at high spin

High spin structure of 84Y.

Transition quadrupole moments in 84Zr.

High-spin structure of 82Y.